Devices for the purpose of arresting lateral swinging of the trailer portion of a tractor-trailer vehicle before it causes the condition known as jackknifing, are well-known in the art. Since some swinging of the trailer is unavoidable and even necessary when negotiating curves, it is not possible to rigidly couple the tractor to the trailer. Certain prior art devices depend upon the driver's judgement for application of the trailer restraining mechanism. Since the lateral movement of the trailer must be kept within a specific range to prevent it reaching the cross-over point which results in jackknifing, such devices have not solved the problem.
Other prior art devices have placed highly complicated mechanisms on the trailer of the vehicle which caused interference with other parts of the trailer, tractor-trailer coupling devices, hydraulic lines and the like, making the coupling and uncoupling of the vehicle time consuming. Since a single tractor may be used for several trailers such devices have proved to be extremely expensive for fleet operators.
Highly complicated, electronically controlled safety devices for restraining swinging motion of the trailer independently of the driver's control have not, proven satisfactory from a reliability and maintenance standpoint.
Accordingly, it is an object of the present invention to provide a trailer control device for tractor-trailer vehicle which will overcome the shortcomings of prior art devices.
Another object of the present invention is to provide a trailer control device which is easily coupled between tractor and trailer and which is between top of the tractor frame and top plate of the fifth wheel of the tractor.
A further object of the present invention is to provide a trailer control apparatus which will cause the trailer to seek a straight or centered position following an undesirable lateral swing without subsequent undue over swing.
Still another object of the present invention is to provide a simplified control apparatus which does not require complicated trailer position sensing equipment or attention from the driver of the vehicle.